Mining machine



Dec. 31, .1929. T. E. PR-AY MINING MACHINE 1926 2 Sheets-Sheet FiledJuly 6 T. E. PRAY MINING MACHINE Dec. 31, 1929.

Filed July 6, 1926 2 Sheets-Sheet mwm WEE. JEN-IL 8 9 mm an Fwenir M pm;

7FZZorJ2 3/ Patented Dec. 31, 1929 UNITE STATES THOMAS E. PRAY, OFCHICAGO, ILLINOIS,

ASSIGNOR TO GOODMAN MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS MINING MACHINE Application filed July 6,

This invention relates to improvements in mining machines and moreparticularly to improvements in the shortwall type of kerf cuttingmining machine adapted to undercut coal and form a kerf which is higherin vertical cross section nearer the working face than at the extremeinner margin of said kerf formed remote from the working face.

A prior application filed by Michael Hardick, on July 15, 1925, SerialNumber 43,668, relates to a machine of the class above men tioned. 1

he principal object of my invention is to provide an improved means forsupporting the cutting elements which discharge the cuttings from bothcutter chains, to provide an improved driving mechanism for the cutterchains, and an improved means for adjusting the cutter chains after theyhave become loosened from wear.

My invention may be best understood by reference to the accompanyingdrawings, wherein I Figure 1 is a top plan view of the device embodyingmy invention:

I Figure 2 is a fragmentary side view of the device illustrated inFigure 1; and

Figure 3 is a sectional view taken on line 3 3 of Figure 1. Likenumerals refer to like parts throughout the various figures.

In these drawings 1 have illustrated a mining machine of the shortwalltype 10, com- 7 prising a main frame 11, having a motor 12 on theforward portion and the usual cutter chain drive gearing and feedmechanism with operating and controlling levers at the rearward portion.An underframe 13 is fixed beneath said main frame and is of large enoughvertical dimensions to accommodate two cutting elements which projectforward- 1y from beneath said, motor.

The aforementioned cutting elements comprise a main cutting element 14which rests in a guide shoe 15 and an auxiliary cutting element16"spaced above said main cutting element by a guide shoe 17 butprojecting forwardly from beneath the motor, only for aportion of thelength of said first mentioned main cutting element. This feature causesthe 1926. Serial No. 120,617.

mining machine to cut a horizontal kerf on the mine bottom which isrelatively wide during a portion of the out near the working face andnarrow at the inner extremities of the out. This causes the coal toeasily roll away from the face when shot down and produces a greaterpercentage of lump coal than could be had if a single narrow kerf wereout since less powder is needed to break the coal away from the face andthe force of the explosion will not break up the coal into small pieces.

The lower or main cutting element 14: comprises a forwardly projectingcutter bar 18 having a cutter chain 19 riding in guides 20, 20, thereon,and the upper or auxiliary cutting element 16 comprises a forwardlyprojec'ting cutter bar 21 having a cutter chain 22 riding in guides 23thereon. The cutter chains 19 and 22 are simultaneously driven bysprockets 24- and 25 respectively. Said sprockets are freely mounted ona vertical shaft 26 and adapted to be operatively connected ordisconnected from said shaft by a single clutch 27 which in this case isa jaw clutch. It may be noted that said sprockets are adapted to beconnected together and in the'construction shown are both integral witha hub 28. The shaft 20 is driven by the motor 12 through a suitablechain of gearing common to mining machines of this class.

Referring now to the method of attaching and holding in alignment thecutter bars 18 and 21, it may be seen that said cutter bars are attachedto the under portion oft'he main frame 11 and the upper portion of theunderframe 13 in the following manner:

'A projection 29 integral with the main frame 11 projects downlongitudinally from beneath said main frame and fits between the innerportion of the rails 30, 30 of the cutter bar 21. A guide and spacingshoe 17 has an upper projection 32 which fits between the rails 30, 30of said upper cutter bar, a central portion 33 to vertically space saidcutter bars at the proper distance, and a lower projection 34 which fitsbetween the rails 35, 35 of the cutter bar 18. A supporting member andguide 15 is fastened to the upper portion of the underframe 1-3 andsupports and aligns the lower portion of the cutter bar 18 and thuskeeps the supporting means and cutting elements in alignment. Bolts 36,36 having nuts 37, 87 thereon, pass through said supporting means tohold said cutting elements to the main frame and underframe. The headsof said bolts 36 bear against the bottom portion ofthe guide 15 whilethe nuts 37 bear against the upper portion of the main frame 11. Thisinsures a rigid connection and accurate alignment of the cuttingelements to the main frame and in addition stiffens the underframe andcutting elements and enables them to withstand lateral thrusts imposedupon them during cutting.

Means are also provided for adjusting the tension of each of the cutterchains to allow for wear of the chains. In the preferable form shownherein, means are provided so that both chains may be adjustedsimultaneously or independently of each other. It is desirable that theadditional provision be made whereby either chain may be adjustedindependent of the other since the cutter chain 011 the main cuttingelement 14 does more Work and is subjected to harder usage thanthe'chain on the auxiliary cutting element 16 and therefore necessarilytends to wear and stretch sooner than the chain on the auxiliary cutterbar, and hence the main cutter chain must be tightened more often thanthe auxiliary cutter chain. To adjust said chains, I provide twoadjusting screws 38 threaded through nuts 89 fixed to the cutter bar 21.The forward ends of said screws bear against the main frame 11. Therearward ends of the screws are provided with suitable heads which maybe gripped by a wrench or other like device. Turning of the screw in onedirection or tightening it causes said screw to bear against the mainframe 11 and tends to push the cutter bar out when the nuts 37, 37 arereleased. Turning in the other direction or loosening releases thepressure of the screws on the frame and leaves the bar free to be pushedbackwards to loosen the cutter chain. In order to adjust the tension ofthe cutter chain 19 as well as of the cutter chain 22, a block 40 isfixed between the rails 30, 30 of the cutter bar 21 and has a downwardprojection which abuts an upward projection on a similar block 41 fixedbetween the rails 35, o5 of the main cutter bar 18. A threaded hole 42passes through the upper projection of the block 41 and is provided witha screw 43 threaded therein. Said screw bears against the projection ofthe block 40.

- Turning of the screw 43 in one direction tends to push the cutter barsapart while turning in the other direction allows the cutter bars to bepushed towards each other. It will thus be seen that simultaneousadjustment of both cutter bars may be obtained by loosening the nuts 37and tightening the screws 38 or vice versa, and independent adjustmentof the cutter bar 18 may be obtained by means of the auxiliary adjustingscrew 43.

Having thus described the various features of the embodiment of myinvention shown herein, it will now be clearly seen that I provide ashortwall type of mining machine having two horizontally extendingcutting elements vertically spaced beneath said mining machine motor inthe space between the under portion of the main frame and the upperportion of the bottom of the underframe. The upper cutting element isshorter than the lower cutting element and a kerf is therefore formedwhich is higher in vertical cross section nearer the working face thanat the extreme inner margins of said kerf formed remote from the workingface. An improved means is provided for supporting and holding saidcutting elements in alignment and an improved means is provided wherebythe tension of both cutter chains may be easily adjusted simultaneouslyor independently. Both cutter chains are driven from a common driveshaft behind the motor and the cuttings may thus be expelled frombeneath the motor and out behind and to the side of the mining machine.

Although I have illustrated and described one form in which my inventionmay be embodied, it will be understood that the construction andarrangement of the various parts may be altered without departing fromthe spirit and scope thereof. I do not there fore wish to be construedas limiting myself to the particular arrangement shown herein, exceptingas it may be specifically limited in the appended claims.

I claim as my invention:

1. In a mining machine adapted to cut a horizontal kerf in a mine wallwider at the outermost extremities than at the innermost extremities, amotor, feed gearing and con trolling mechanism rearward of said motor, amain forwardly extending cutter chain carrying kerf cutting elementbeneath said motor, an auxiliary cutter chain carrying kerf cuttingelement above said first named cutting element but beneath said motorand extend ing forwardly for a portion of the length of the firstmentioned main cutting element, a plurality of chain driving sprocketsextending beneath said motor and mounted on a common drive shaftrearward of said motor ting element but beneath said motor and extendingforwardly for a portion of the length of the first mentioned maincutting element, a plurality of chain driving sprockets extendingbeneath said motor and mounted on a common drive shaft rearward of saidmotor to simultaneously drive both of said cutter chains, and meanswhereby the tension of said cutter chains may be adjusted simultaneouslyor independently.

Signed at Chicago, in the county of Cook and State of Illinois, this30th day of June,

THOMAS E. PRAY.

